This invention relates to an image display control method and apparatus for outputting an image display signal to a display device to display an image on the device.
An image display system known in the art includes an image display controller and a display unit connected via a digital interface. In such an image display system, image data is transmitted from the image display controller to the display unit via the digital interface and, in addition, control data for requesting various operations is transmitted from the display controller to the display unit via the digital interface.
In an arrangement of this kind, the command data usually is transmitted at a timing different from that of the image data. However, in instances where a high-resolution image is displayed as in the case of high-definition television, for example, a very large quantity of image data is involved. If the command data is inserted during interims of the image data, therefore, little time is available for transmission of the command data. In particular, when the amount of command data transmitted from the display controller to the display unit is very large, time for transmission of the command data can no longer be assured.
Accordingly, an object of the present invention is to provide an image display control method and apparatus for reducing the amount of image data to be transmitted, thereby assuring idle time in transmission of the data, and for transmitting command data during this idle time.
Another object of the present invention is to provide an image display control method and apparatus for transmitting command data between items of image data while eliminating dedicated transmission means for transmission of command data.
A further object of the present invention is to provide an image display control method and apparatus in which when image data is transmitted to one display unit of a plurality of display units mounted in a display device, command data is transmitted using an image-data line signal of another of the display units.
According to the present invention, the foregoing objects are attained by providing an image display control apparatus for outputting an image signal to a display device to thereby display an image on the display device, comprising: reducing means for reducing the amount of image data, which is to be transmitted to the display device, in comparison with display resolution of the display device; transmitting means for transmitting the image data, the amount of data whereof has been reduced by the reducing means, to the display device together with a synchronizing signal; and control-data transmitting means for transmitting control data to the display device over a period of time commensurate with the amount of data that has been reduced.
According to the present invention, the foregoing objects are attained by providing an image display control method for outputting an image signal to a display device to thereby display an image on the display device, comprising: a reducing step of reducing the amount of image data, which is to be transmitted to the display device, in comparison with display resolution of the display device; a transmitting step of transmitting the image data, the amount of data whereof has been reduced at the reducing step, to the display device together with a synchronizing signal, and a control-data transmitting step of transmitting control data to the display device over a period of time commensurate with the amount of data that has been reduced.
The display device displays the image data of the reduced amount upon performing an interpolation in conformity with the display resolution of the display device.
Preferably, line data in one vertical scanning interval is downsampled on a per-line basis in order to reduce the amount of image data to be transmitted to the display device.
Preferably, line data in one horizontal scanning interval is downsampled on a per-pixel basis in order to reduce the amount of image data to be transmitted to the display device.
Preferably, odd-numbered line data is transmitted in an initial vertical scanning interval and even-numbered line data is transmitted in the next vertical scanning interval in order to reduce the amount of image data to be transmitted to the display device.
Preferably, a control signal for distinguishing between transmission of image data and transmission of control data is provided.
Preferably, the frequency of the synchronizing signal is made one frequency when the image data is transmitted and a different frequency when the control data is transmitted in order to distinguish between transmission of image data and transmission of control data.
An arrangement may be adopted in which the display device has a plurality of display units (display panels), image data is transmitted to one of the display units and control data is sent to the display device at a transmission timing of display data that is transmitted to another of the display units. In this case, it will suffice to display an image on only one display unit, or the display device may interpolate received image data and display the results on a plurality of display units.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.